HEIC1006: EMBARGOED UNTIL 16:00 (CEST)/10:00 AM EST 08 April, 2010
http://www.spacetelescope.org/news/html/heic1006.html
Photo release: Hubble snaps heavyweight of the Leo Triplet
08-April-2010 Hubble has snapped a spectacular view of the largest “player” in the
Leo Triplet, a galaxy with an unusual anatomy: it displays asymmetric spiral arms
and an apparently displaced core. The peculiar anatomy is most likely caused by the
gravitational pull of the other two members of the trio.
The unusual spiral galaxy, Messier 66, is located at a distance of about 35 million light-
years in the constellation of Leo. Together with Messier 65 and NGC 3628, Messier 66 is
one third of the Leo Triplet, a trio of interacting spiral galaxies, part of the larger Messier
66 group. Messier 66 wins out in size over its fellow triplets — it is about 100 000 light-
years across.
Messier 66 is the proud owner of exclusive asymmetric spiral arms which seem to climb
above the galaxy’s main disc and an apparently displaced nucleus. This asymmetry is
unusual; most often, dense waves of gas, dust and newly born stars wind about the
galaxy’s centre in a symmetric way. Astronomers believe that Messier 66’s once orderly
shape has most likely been distorted by the gravitational pull of its two neighbours.
Hubble has imaged Messier 66’s striking dust lanes and bright star clusters along the
spiral arms in fine detail with the Advanced Camera for Surveys. Star clusters — pictured in
the blue and pinkish regions of the image — are key tools for astronomers since they are
used as indicators of how the parent galaxies assembled over time.
Messier 66 boasts a remarkable record of supernovae explosions. The spiral galaxy has
hosted three supernovae since 1989, the latest one occurring in 2009. A supernova is a
stellar explosion that may momentarily outshine its entire host galaxy. It then fades away
over a period lasting several weeks or months. During its very short life the supernova
radiates as much energy as the Sun would radiate over a period of about 10 billion years.
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Notes for editors
The Hubble Space Telescope is a project of international cooperation between ESA and
NASA.
Image credit: NASA, ESA and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration.
Acknowledgement: Davide De Martin and Robert Gendler
For more information, please contact:
Colleen Sharkey
Hubble/ESA, Garching, Germany
Tel: +49-89-3200-6306
Cell: +49-0151-1537-3591
E-mail: csharkey@eso.org